Jay Giggles or Uncle Giggles, was a rich eccentric practical joker whose jokes drive Fred into a mad rage. He is from Fredd's Father's side of the family. His first and only appearance was in the seventh episode of the fifth season intitled "A Haunted House Is Not A Home".
Fred's Uncle Giggles fakes his death and pretends that he has left his fortune to Fred. In order to get the fortune, Fred was required to stay overnight at Giggle's haunted house on Nightmare Hill. While thare, it appears that Fred gets nearly killed by Giggle's three servents Creepers the butler, Hotrock the cook, Wormstone the gardener. The next morning, Fred's Uncle Giggles shows up and says the whole thing was a joke.
His lawyer is Mr. Blackstone and he owns a pet giant taradactle named Horris; who injoys reading tombstones at the local cemetery. Fred only saw his Uncle Giggles twice in his life and says he is the cuckoo of the family.